General Knowledge - Biology - Discussion

@All.
According to me, Option 1) I and II are correct is the correct answer.

Fish have a swim bladder, which is a gas-filled sac that helps them control their buoyancy and stay afloat at different water depths. The swim bladder adjusts the fish's buoyancy by changing its volume, which is regulated by the fish's gas gland and rete mirabile. The gas in the swim bladder is typically oxygen or nitrogen. The presence of a swim bladder helps the fish to avoid sinking in the water.

So, a statement I is correct.

Air bladder and air sacs are not present in fish. Air sacs are present in birds which help them in respiration. So, statements III and IV are incorrect.

Most fish do not sink in water due to the presence of a swim bladder, which is a gas-filled organ located in their abdominal cavity. The swim bladder allows fish to regulate their buoyancy by adjusting the amount of gas (usually oxygen) inside it.

How it Works:

When a fish wants to rise, it increases the gas in the swim bladder, making it more buoyant.
When it wants to sink, it releases gas, reducing buoyancy.
The swim bladder helps fish maintain their position in water without continuously swimming, saving energy.

Fishes do not sink in water because swim bladder keep the fish on water surface if it is filled with air. But if fishes want to sink to ward the bottom of water they open swim bladder and release air in it. If there is no air in swim bladder the fishes weight increase and the simply sink in water.

The swim bladder and air bladder are internal gas-filled organs that contribute to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their current water depth without sinking or having to waste energy in swimming.

The swim bladder is located in the body cavity and is derived from an out-pocketing of the digestive tube.

It contains gas (usually oxygen) and functions as a hydrostatic, or ballast, organ, enabling the fish to maintain its depth without floating upward or sinking.

It can't be a swim bladder that helps a fish swim because I doesn't make any sense. The truth is that air sacs and spongy bones help fish to swim and it makes sense.

Most of the fishes contain swim bladder and gall bladder. They are used as to float. Due to the presence of air in the bladder they don't sink in water.

Swim blader helps to the fish to swim and the air blader contain air it helps the fish to float in the water.
Then I want to know which fish it is.

I think swim blade help them to swim continue in water and air blade also decrease their density that's why most of fishes don't sink in water.

This is always true. They swim without sink b/c they contain swim bladder and they float freely b/c they involve air in their bladder.